Barrier-less prefilled via formation

Abstract

A method for fabricating a semiconductor device includes forming one or more layers including at least one of a liner and a barrier along surfaces of a first interlevel dielectric (ILD) layer within a trench, after forming the one or more liners, performing a via etch to form a via opening exposing a first conductive line corresponding to a first metallization level, and forming, within the via opening and on the first conductive line, a barrier-less prefilled via including first conductive material.

What is claimed is: 
     
       1. A semiconductor device, comprising:
 a first conductive line corresponding to a first metallization level; 
 a first cap layer disposed on the first conductive line; 
 a first interlevel dielectric (ILD) layer disposed on the first cap layer; 
 one or more layers including at least one of a liner and a barrier disposed along surfaces of the first ILD layer within a trench formed in the first ILD layer; 
 a second conductive line corresponding to a second metallization level disposed on the one or more layers; 
 a barrier-less prefilled via disposed in direct contact with the first and second conductive lines and the first ILD layer; 
 a second cap layer disposed across the first ILD layer, the one or more layers and the second conductive line; and 
 a second ILD layer disposed on the second cap layer. 
 
     
     
       2. The device of  claim 1 , wherein the barrier-less prefilled via includes a protrusion extending to a height above a top surface of the one or more layers, the protrusion gouging into the second conductive line to further reduce via resistance. 
     
     
       3. The device of  claim 2 , wherein the protrusion has a top with a circular-shaped profile. 
     
     
       4. The device of  claim 2 , wherein the protrusion has a top with a conical-shaped profile. 
     
     
       5. The device of  claim 2 , wherein the protrusion has a top with a convex-shaped profile. 
     
     
       6. The device of  claim 1 , wherein the barrier-less prefilled via has a rectangular-shaped profile. 
     
     
       7. A semiconductor device, comprising:
 a first conductive line corresponding to a first metallization level; 
 a first cap layer disposed on the first conductive line; 
 a first interlevel dielectric (ILD) layer disposed on the first cap layer; 
 one or more layers including at least one of a liner and a barrier disposed along surfaces of the first ILD layer within a trench formed in the first ILD layer; 
 a second conductive line corresponding to a second metallization level disposed on the one or more layers; 
 a barrier-less prefilled via disposed in direct contact with the first and second conductive lines, with the barrier-less prefilled via having extensions on a top surface of the one or more layers; 
 a second cap layer disposed across the first ILD layer, the one or more layers and the second conductive line; and 
 a second ILD layer disposed on the second cap layer. 
 
     
     
       8. The device of  claim 7 , wherein the barrier-less prefilled via has a rectangular-shaped profile. 
     
     
       9. The device of  claim 7 , wherein the barrier-less prefilled via includes a protrusion extending to a height above a top surface of the one or more layers, the protrusion gouging into the second conductive line to further reduce via resistance. 
     
     
       10. The device of  claim 9 , wherein the protrusion has a top with a circular-shaped profile. 
     
     
       11. The device of  claim 9 , wherein the protrusion has a top with a conical-shaped profile. 
     
     
       12. The device of  claim 9 , wherein the protrusion has a top with a convex-shaped profile. 
     
     
       13. A semiconductor device, comprising:
 a first conductive line corresponding to a first metallization level; 
 a first cap layer disposed on the first conductive line; 
 a first interlevel dielectric (ILD) layer disposed on the first cap layer; 
 one or more layers including at least one of a liner and a barrier disposed along surfaces of the first ILD layer within a trench formed in the first ILD layer; 
 a second conductive line corresponding to a second metallization level disposed on the one or more layers; 
 a barrier-less prefilled via disposed in direct contact with the first and second conductive lines, with the barrier-less prefilled via including a protrusion extending to a height above a top surface of the one or more layer; 
 a second cap layer disposed across the first ILD layer, the one or more layers and the second conductive line; and 
 a second ILD layer disposed on the second cap layer. 
 
     
     
       14. The device of  claim 13 , wherein the barrier-less prefilled via has a rectangular-shaped profile. 
     
     
       15. The device of  claim 13 , wherein the protrusion gouges into the second conductive line to further reduce via resistance. 
     
     
       16. The device of  claim 13 , wherein the protrusion has a top with a circular-shaped profile. 
     
     
       17. The device of  claim 13 , wherein the protrusion has a top with a conical-shaped profile. 
     
     
       18. The device of  claim 13 , wherein the protrusion has a top with a convex-shaped profile.